Heat exchanger



Jan. 27, 1959 s'. sDERsTRoM 2,370,997

HEAT EXCHANGER Filed June 4. 1954 '3 sheets-sheet 2 INVENTOR Ste72 oa/ersrom BY 52 :SJW QA/W4 65 ATToRNEYa Jan. 27, 1959 s. SDERSTROM HEAT EXCHANGER 5 Sheets-Sheet 3 FiledJune 4. 1954 FIGJ/ 5 305/543536 INVENTOR:

Ste72 50de rstrom ATTORNEY.

Cams or guide blades 18 are preferably secured to the wall delimiting the ilow passages 6, 17 in an inward direction, that is to say, to the outsides of the tubes and 12, in a manner such that said cams or guide blades have their bases at said wall and their tops at or in the proximity of the opposite wall of the clearance, that is to say, at the housing land at the tube 8, respectively. Said cams or guide blades are intended to improvefthe heat transfer. Examples of their construction are shown in Figs. 7-9.

Secured in the end wall 2 is an inlet pipe 19 for the heating medium, such as steam, and an outlet pipe for the heating medium or for condensate formed by the same. These pipes are open toward the space 21 formed about the tube 8 between the latter and the tube 5. Likewise, the space 22 within the double-tube 12, 15 is in communication with an inlet socket 23 for a heating medium, such as steam, and with an outlet socket 24 for said medium or lor condensate formed thereby.

Arrows 25 indicate how the medium to be heated ows from the inlet 4 into the flow passage 6, through the passage 11 and the passage 17 in a direction back toward the passage 14, and from the latter through the innery most tube 15 to the outlet 16.

Arrows 26 and 27 indicate the path of the heating medium from the inlets 19 and 23 to the outlets 20 and 24, respectively.

The arrangement described may be simpliiied by single tubes being substituted for the double-tubes, inlet and outlet sockets being then arranged correspondingly for the different media.

The capacity of the heat exchanger may be increased considerably without changing the length thereof, by forming the heat exchanger with a plurality of doubletubes within one another. Such a tube might be designated a multiple-tube. Examples of such tubes are shown in Fig. 2. Here, the outer housing 1, the end walls or plates 2, 3, the inlet socket 4 for the medium to be heated, such as oil, and the outermost double-tube 5, 8 have the same designations as in Fig. l. Instead of terminating in an end wall 9, as in Fig. 1, the inner tube 8 here merges into a further double tube 30, 31 located within the tube 8, said double-tube continuing at the end wall 2 into an inner tube 32 having a closed end 33 in the propinquity of the opposite end wall 3. Arranged in the end wall 3 is also a multiple-tube composed of two double-tubes, namely the multiple-tube 34, 35, 36, 37, the several tubes of the multiple tubes projecting into one another. The innermost tube 37 projects through the end wall 3 of the exterior thereof and here forms an outlet 38 for the medium that has been heated. The heating medium is introduced into the tube 5 through a pipe 39 extending into the space between the tube walls 5 and 3 and through pipes 40 and 41 branched 0E from the pipe 39 and extending into the intermediate space between the tubes and 31 and into the tube 32, respectively. Likewise, heating medium is introduced through an inlet 42, arranged in the opposite end wall 3, into pipes 43, 44, the latter of which is branched off from the pipe 43. On having given off heat, this medium escapes, perhaps in the form of condensate, through an outlet 45 in the end wall 2 and an outlet 46 in the end wall 3. How the heat-absorbing medium ilows is shown by the arrows 47, the path of the heat-yielding medium being indicated by the arrows 48. v

Fig. 3 is a detail view illustrating the manner of securing the tube 5 to the end wall 2 and the manner in which the pipe 39 passes therethrough. V

In Figs. ll-l6 the same reference numerals are used as in Fig. 2 to indicate corresponding elements. Fig. 1l illustrates the same section as Fig. 2, i. e. an axial section of the assembled heat exchanger in ka somewhat simplified manner, Fig. l2 shows the housing 1 with its inlet socket d for the medium to be heated, Fig. 13 the left end plate 2 with its multiple tube 5, 8, 30, 31, 32,

Fig. 14 the right end plate 3 with its multiple tube 34, 35, 36, 37 and Figs. 15 and 16 cross sectional views of the parts of the heat exchanger shown in Figs. 13 and 14 respectively. It is clear from Figs. 12-13 in what manner the heat exchanger may be assembled, i. e. simply by thrusting the end plates 2 and 3 with their corresponding multiple tubes from opposite directions into the housing 1 to the position illustrated in Fig. ll. lt is also clear from Fig. ll that the multiple tube 5, il, .3u-w31, 32 is secured to its end plates 2 only at its one end but is free at itslother end so as to be able to expand at changes of temperature without influencing the opposite end plate 3. The same applies to the multiple tube 34, 35, 36, 37 with regard to the end plates 3 and 2.

In the construction according to Figs. 4-5, a multipletube Stb, consisting of tive tubes located within each other and integral at the ends thereof, is united with the end wall 2, that is to say through the left end of the outermost tube, as shown in Fig. 4. In a similar' manner, a multiple tube 51, consisting of four tubes located within each other and integral at thel ends thereof, is secured to the end wall 3 by the outermost tube of said multipletube, so thatsaid tubes are caused to project in between the part tubes of the multiple tube 50 while being free from said tubes and forming flow passages for the heatexchanging media. In v order that the heat-yielding medium, which may be constituted by a liquid, shall be conveyed from one end to the other of the tubes, special guide tubes are provided in the spaces traversed by the heat-yielding medium. Thus there are two such coaxial guide tubes 52, 53 secured to the end wall 2 and two similar guide tubes 54, 55 secured in the end wall 3. The medium to be heated ows as indicated by the arrows 56 from the inlet 57 to the outlet 58, whereas the heatyielding medium flows from the inlet 59 in the end wall 2 to the outlet through a central pipe 61, as shown by the arrows 60, and from the inlet 62 in the opposite end wall 3 to an outlet 63, as shown by the arrows 64.

Inasmuch as the heat-absorbing med-ium ows from a passage or channel adjacent to the inlet with a progressively smaller diameter inwardly toward the center of the apparatus, where it escapes, it is obvious that the passage area thereof is reduced, according as the heating proceeds. Hereby the velocity of the medium is also increased. At the inlet, where the medium may be conceived of as being comparatively viscous, the resistance to the flow will still be moderate owing to the large passage area, and when heated the medium becomes more liquid, for which reason the velocity thereof may be increased, without the resistance to the flow becoming too great.

Figs. 7, 8 and 9 show various arrangements of the cams or guide blades 18 arranged in the channels for the heat-absorbing medium. These cams may be welded or secured otherwise in rows along the tube walls and the cams in each row extend in a generally radially outward direction as related to the longitudinal axis of the tube. Each cam is twisted, so that the base 65 and the top 66 thereof form an angle with one another. In Figs. 7-9, where the arrows 67 indicate the longitudinal direction of the tubes (the principal direction of flow of the medium), two cams are shown in each of two adjacent rows. In Fig.` 7, the cams are arranged peripherally and laxially opposite one another while being twisted in opposite directions; in Fig. 8, the cams are likewise arranged peripherally and axially opposite one another, but are twisted in the same direction; and in Fig. 9 they are 'displaced axially by half a cam width and twisted in opposite directions.

The cams form a meandering passage for the medium 'and break the laminary flow thereof and increase the heat transferring surface, whereby the transfer of heat is highly improved.

Through the twisting of the cams, the medium owing between them will also obtain a direction of movement inwardly toward the base of the cam, the medium being copper alloy.

gardes? uns 'compenea "to mve against the neat-yielding tube Wall.

The "cams are prefrablyinad'e fromthe 4saine kind of material as "are the t'bes, for instance from "malleable iron br"`som`e acid-`prof `iron alloy, "aluminium alloy or Owingto the arran`ge`-"e1it of "the `ttilies` yas 'described with the tubessecu'rd in "separate end `walls and having the "inner ends thereof free, 'the heat 'exchanger may` be readi1yeismaatf1ea the earns being located in easily ac- 70, 71 merge `one into the other at `their inner ends, which fare free from the end walls, fthe Atubes thus `forming `a `double tube with a chamber 75 therebetween for one medium, for example steam, whichfis `admitted through the inlet 7L6and escapes, usually as acondensate,` through the outlet 77. There is a central inlet 78 at the end wall 73 for the other medium, for example oil, and an outlet 79 in the end wall 72 for. the same. A cup shaped guide wall or member 80 is secured to the double tube 70, 71 by spider 81 and a bolt 82 and extends around the tubes 70, 71 toward the carrying end wall 72. It terminates in spaced relation from the latter to form an annular passage 83 for the medium which flows in the direction indicated by the arrows 84.

It is evident that the capacity of the heat exchanger of the type illustrated in Figs. 17-18 can be improved by substituting for the double tube 70, 71 a multiple tube of the type illustrated in Fig, 2, a plurality of coaxial guide cups of the same type as the guide wall 80 being mounted one within the other and in the spaces between the double tubes of the multiple tube.

The embodiment shown in Figs. 17-18 brings the advantage that all tubes are carried by one end wall and are carried along with the latter at the removal from the housing. Furthermore an even distribution of the medium entering the inlet 78 is also gained by this embodiment, and if the entering medium has the temperature of the surrounding atmosphere the heat exchanger need not be heat-insulated outwards, since the entering medium fiows in contact with the housing 74 before contacting any wall heated by the other medium.

In connection with the examples of embodiment shown, the invention has been described as referring to a heating apparatus, but obviously the same principle may be applied to coolers.

What I claim is:

1. Heat exchanger comprising a housing including opposite end walls and a side wall therebetween, a first multiple tube comprising an outer tube secured at one end thereof to one end wall of said housing, the opposite end of said outer tube being turned inwardly to form the corresponding end of an inner tube within said outer tube, the opposite end of said inner tube being closed and being located in the proximity of but in spaced relation from that end wall of said housing to which said outer tube is secured; a second multiple tube comprising an outer tube secured at one end to the opposite end wall of said housing and extending into an end of the inner tube of said first multiple tube, the opposite end of said outer tube terminating in the proximity of but in spaced relation from the closed end of said inner tube of said first multiple tube and being turned inwardly to fonn the corresponding end of an inner tube within said outer tube and which extends longitudinally within said outer tube, the opposite end of said inner tube being closed and being located in the proximity of but in spaced relation from said opposite end wall of said housing, said tubes of said rst and second multiple tubes being spaced from each other and from the side wall of said housing; a pipe connection for a first G t medium into one end of said housing betweensaidlhousing and the outer tube of` said first multiple tube, a pipe connection for that said. rs't medium into the inner tube of said second multiple tube at the opposite end of said housing, inlet and outlet pipe connections for a second medium through one end of said housing and into the space between the inner and` outer tubes of said first multiple tube, and inlet andv outlet pipe connections` for `said' second medium through the opposite end of said housing and into the` space between ythe outer and inner tubes of said second multiple tube.

2.` Heat exchanger `a`s claimed in claim l, in which the spaces betweensaid tubes form flow passages,` one for the heat delivering 'medium and another for a viscous heat receiving medium, the cross-sectional area` of the latter passage decreasing successively from an inlet for the` medium being heated to an outlet for the same medium.

`3. Heat exchanger as claimed in claim l, in which the spaces `between said tubes form flow passages, one for a cooling medium and another for atmedium tobe cooled, the cross-sectional 'ar'ea of the latter passage increasing successively from an inlet for the medium to be cooled to a'n butletforthe same medium.

4. Heat exchanger comprising a housing including opposite end walls and a side wall therebetween, a first multiple tube comprising an outer tube secured at one end thereof to a first end wall of said housing, the opposite end of said outer tube being turned inwardly to form the corresponding end of a first inner tube within said outer tube, the opposite end of said first inner tube being located in the proximity of but in spaced relation from that end wall of said housing to which said outer tube is secured, said opposite end of said first inner tube being turned inwardly to form the corresponding end of a second inner tube within said first inner tube, the opposite end of said second inner tube being closed and spaced from the second and opposite end wall of said housing; a second multiple tube comprising an outer tube secured at one end thereof to said second end wall of said housing and extending into an end of said first inner tube of said first: multiple tube and being spaced therefrom, the opposite end of said outer tube of said second multiple tube terminating in the proximity of but in spaced relation from the inwardly turned end of said rst inner tube of said first multiple tube and itself being turned inwardly to form 'the corresponding end of a first inner tube within said outer tube of said second multiple tube, the oposite end of said first inner tube of said second multiple tube terminating in the proximity of but in spaced relation from said second end wall of said housing to which said outer tube of said second multiple tube is secured, said opposite end of said first inner tube of said second multiple tube being turned inwardly to form the corresponding end of a second inner tube located within said first inner tube of said second multiple tube and spaced therefrom, said tubes of said first and second multiple tubes being spaced from each other and from the side wall of said housing; an inlet pipe for a first heat exchanging medium leading to the housing space between said end walls and the outer side of said outer tube of said first multiple tube, an exit pipe for said first heat exchanging medium connected 'to the opposite end of said second inner tube of said` second multiple tube, an inlet pipe for a second heat exchanging medium leading through said first end wall into a first enclosed space between the outer tube and inner tubes of said first multiple tube, an outlet pipe for said second heat exchanging medium from said first enclosed space, a second inlet pipe for said second heat exchanging medium leading through said second end wall into a second enclosed space between the outer tube and inner tubes of said second multiple tube, and a second outlet pipe for said second heat exchanging medium from said second enclosed space.

5. Heat exchanger as defined in claim l and comprising an inlet pipe for one medium extending through said 7 one end wall of said housing into the space between the outer tube and the inner tube of the multiple tube carried by said one end wall, said pipe opening into said space near the place where the inner end of said outer tube is turned inward to mergeinto the inner tube.

6. Heat exchanger comprising a tubular housing, an end plate removably attached to each end of said housing, first and second series of coaxial tubes merging into one another alternately at opposite ends, the outermost of the tubes in said first series being secured to one end plate at one of its ends only and the other of said ends carrying the remaining tubes of said rst series, the outermost tube of said second series being secured to the other end plate and the innermost tube of said second series passing 'f through the latter end plate, the rst series being supported by its end plate only but being unsupported by and spaced from the end plate carrying the second series, the tubes of one series further extending into spaces between tubes of the other series to form a ilow passage for one heat exchanging medium in the housing between said series `of tubes from a point at or near the periphery of the housing to the place where the innermost tube of the second series passes through its end plate, each series of tubes also forming, together with the end plate carrying said series, a space for the other heat exchanging medium.

7. Heat exchanger as claimed in claim 6 and further having guide pipes eachv of which is secured at one end to one end plate and open at its other end, said other end extending into the space formed between the corresponding series of tubes and end plate, the inner open end of each guide pipe being located near the place of transition between two consecutive tubes of the series but spaced therefrom to allow heat exchanging medium to pass from'one side of the guide pipe past the inner end thereof and to the other side thereof.

References Cited in the le of this patent UNITED s TATEs PATENTS 997,762 Derrig July 1l, 1911 1,880,533 Thomas Oct. 4, 1932 2,181,927 Townsend Dec. 5, 1939 2,372,079 Gunter Mar. 20, 1945y 2,418,619 Brown Apr. 8, 1947 2,428,145 Cook Sept. 30, 1947 

